Vent including a separator membrane

ABSTRACT

A vent structure at least partially defining a passageway between the inside of a fuel storage tank and the outside atmosphere includes a separator membrane. The separator membrane is positioned within the vent structure configured to block liquid fuel in the storage tank from reaching the outside atmosphere through the passageway. The separator membrane is permeable by air. The vent structure may be in the form of a cap or a remote vent, or it may be provided substantially within the fuel storage tank. The vent structure may be provided as part of a fuel evaporative emissions system for a vehicle or motor-driven power equipment.

RELATED APPLICATIONS

The present application claims priority to U.S. Patent Application Ser.No. 60/760,674, filed Jan. 20, 2006, entitled LOCKING CAP, and to U.S.Patent Application Ser. No. 60/760,613, filed Jan. 20, 2006, entitledMODULAR RATCHET CAP, and to U.S. Patent Application Ser. No. 60/760,670,filed Jan. 20, 2006, entitled VENT INCLUDING A SEPARATOR MEMBRANE, andto U.S. Patent Application Ser. No. 60/862,074, filed Oct. 19, 2006,entitled VENT INCLUDING A SEPARATOR MEMBRANE, and to U.S. PatentApplication Ser. No. 60/862,077, filed Oct. 19, 2006, entitled LOCKINGCAP, and to U.S. patent applicataion Ser. No. ______ (Attorney DocketNo. 053196-9020-02), filed Jan. 19, 2007, entitled LOCKING CAP, and toU.S. patent application Ser. No. ______ (Attorney Docket No.053196-9021-01), filed Jan. 19, 2007, entitled MODULAR RATCHET CAP, theentire contents of all of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a vent arrangement and, moreparticularly, to a cap for a fuel tank or remote vent for a fuel systemand including a membrane.

SUMMARY OF THE INVENTION

In independent aspects and in some constructions, the invention providesa cap for closing an opening, such as the filling tube on a fuel tank,the cap generally including a cap housing operable to close the opening,a structure supported by the housing and defining a vent, the ventallowing the flow of gas (e.g., air) therethrough, and a membranepositioned in a flow path and presenting flow of one or more selectedfluids (e.g., liquid, fuel, harmful gases, etc.) from existing the vent.

In independent aspects and in some constructions, the invention providesa vent for a closed system, such as a fuel system, the vent generallyincluding a vent housing in fluid communication with the system, astructure supported by the housing and defining a vent, the ventallowing the flow of gas (e.g., air) therethrough, and a membranepositioned in a flow path and preventing flow of one or more selectedfluids (e.g., liquid, fuel, harmful gases, etc.) from exiting the vent.In some constructions, the vent generally includes a remote vent.

Independent features and independent advantages of the present inventionwill become apparent to those skilled in the art upon review of thedetailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a fuel storage system having a ventedmembrane cap;

FIG. 2 is an exploded assembly view of the vented membrane cap of FIG.1;

FIG. 3 is perspective view of the vented membrane cap of FIG. 1;

FIG. 4 is a cross-sectional view of the vented membrane cap of FIG. 1,taken along line 4-4 of FIG. 3;

FIG. 5 is an exploded assembly view of a vented membrane cap accordingto another embodiment of the invention;

FIG. 6 is a schematic view of a fuel storage system including the ventedmembrane cap of FIG. 5;

FIG. 7 is an exploded assembly view of a remote vent according toanother embodiment of the invention;

FIG. 8 is a cross-sectional view of the remote vent of FIG. 7;

FIG. 9 is a schematic view of a fuel storage system including the remotevent of FIG. 7;

FIG. 10 is a schematic view of a fuel storage system including abottom-vented membrane-separated vent head according to anotherembodiment of the invention; and

FIG. 11 is a schematic view of a fuel storage system including amembrane-capped vent tube positioned within a storage tank volumeaccording to yet another embodiment of the invention.

Before any independent features and at least one embodiment of theinvention are explained in detail, it is to be understood that theinvention is not limited in its application to he details of theconstruction and the arrangement of the components set forth in thefollowing description or illustrated in the drawings. The invention iscapable of other embodiments and of being practiced or of being carriedout in various ways. Also, it is understood that the phraseology andterminology used herein is for the purpose of description and should notbe regarded as limiting.

Although references are made below to directions, such as left, right,up, down, top, bottom, front, rear, forward, back, etc., in describingthe drawings, the reentries are made relative to the drawings (asnormally viewed) for convenience. These directions are not intended tobe taken literally or to limit the present invention in any form.

The use of “including”, “having”, and “comprising” and variationsthereof herein is meant to encompass the items listed thereafter andequivalents thereof as well as additional items. The use of letters toidentify elements of a method or process is simply for identificationand is not meant to indicate that the elements should be performed in aparticular order.

DETAILED DESCRIPTION

FIGS. 1-4 illustrate a fuel storage system 20 and components thereof,including a cap 25 for closing an opening 30, such as on a fuel tank 35.In the illustrated embodiment, the cap 25 includes threads 40 for matingwith corresponding threads (not shown) on the opening 30. The cap 25serves as a venting structure, which a lows for passage of air from aninside of the fuel tank 35 to an outside of the fuel tank 35 and/or viceversa. The venting structure allows venting of air into and out of thefuel tank 35 while blocking the passage of liquid, such as gasoline,diesel, etc. In some embodiments, the venting structure also blocks thepassage of fuel vapor volatile organic compounds (VOCs), etc. whileallowing the passage of select gases, including air.

The cap 25 of the illustrated embodiment is simply constructed of a mainbody portion 50 having a venting aperture 55 formed centrally therein.The main body portion 50 is also formed to include the threads 40 forengaging the opening 30 when the cap 25 is installed thereon, the gasket60 for forming a circumferential seal between the cap 25 and the opening30. The main body portion 50 includes an outer circumferential wall 65projecting outwardly (away from the fuel tank 35). A cover 70 is coupledto the main body portion 50 adjacent the outer circumferential wall 65to define a substantially enclosed chamber 75 with the main body portion50. The cover 70 includes a vent hole 80 providing limited communicationbetween the chamber 75 and the atmosphere outside the cap 25. The mainbody portion 50 further includes an inner circumferential wall 85radially inward of the outer circumferential wall 65, and projecting inthe same direction as the outer wall 65.

A separator membrane 90 is supported by the cap 25. The separatormembrane includes a peripheral rim portion 92 having a larger thicknessthan a central portion 94. In the illustrated embodiment, the membrane90 is supported at its peripheral rim portion 92 by the innercircumferential wall 85 of the main body portion 50 such that it ispositioned within the chamber 75. In the illustrated construction, themembrane 90 is in communication with the venting aperture 55 on one side(the “interior” side) and in communication with the vent hole 80 on theopposite side (the “exterior” side). The membrane 90 is generally planarand disk-shaped in the illustrated embodiment. The membrane 90 isconstructed of a material, as discussed in greater detail below, whichis impermeable to liquids such as gasoline and diesel fuel.

The membrane 90 is joined to the inner circumferential wall 85, whichmay be constructed of a plastic material, in a liquid leak-free manner.In some constructions, the membrane 90 may be welded to the plastic ofthe vent, and, in such constructions, a weld material/layer may be addedto the interface between the membrane 90 and the inner circumferentialwall 85. In some constructions, the membrane 90 may be welded byultra-sonic welding, spin welding, etc. to the inner circumferentialwall 85. In such constructions, an additional weld material/layer maynot be necessary and, therefore, may not be added.

In other constructions, other methods/structures (e.g., adhesives,molding (including insert molding), and sandwiching between adjacentparts, etc.) may be employed as methods of mounting or joining themembrane 90 to the main body portion 50. Any of the fastening and/orscaling methods described herein are also applicable to alternate ventstructures (regardless of whether they are caps or not) using a membranesimilar to the membrane 90 (regardless of the exact form of themembrane). Generally, when the membrane 90 is joined with a plasticcomponent, a membrane assembly is created that may be employed invarious applications including different styles of vents (e.g., cap,remote rollover, etc.) different sizes, etc. In some constructions, themembrane 90 provides a liquid/vapor separation between a tank and acarbon canister or air cleaner.

The cap 25 defines a flow path from the fuel tank 35 to the outsideatmosphere. The membrane 90 is positioned in the flow path between theinterior of the fuel tank 35 and the exterior of the cap 25 opposite thefuel tank. Accordingly, for any gaseous fluid to pass from the inferiorof the fuel tank 35 to the outside atmosphere or vice versa, suchgaseous fluid must pass through the membrane 90.

In one construction, the membrane 90 is constructed of a material thatis impermeable to liquid (e.g., gasoline, diesel fuel, etc.) such thatthe fuel tank 35 is vented to the atmosphere through the flow path ofthe cap 25, and a separate rollover valve is not necessary to keepliquid from escaping the fuel tank 35 through the flow path. Themembrane 90 acts as a rollover leak protection mechanism, which has nomoving parts to be relied upon. The cap 25 as a whole is a ventingstructure with built-in rollover leak protection, which isadvantageously provided in the form of the inert membrane 90.

In another construction, the membrane 90 is constructed of a materialthat is impermeable to liquid (e.g., gasoline, diesel fuel, etc.) andalso impermeable to fuel vapor while being permeable to air. As usedherein, fuel vapor refers to the majority of chemical compounds thatcommonly evaporate from liquid gasoline, diesel fuel, etc. These areoften referred to as VOCs, the release of which are regulated andrestricted by certain federal, state, and/or local regulations for manyapplicators. In this construction, the cap 25 is a venting structurewith built-in rollover leak protection as well as evaporated fuel vaporblocking.

When the cap 25 is installed on the opening 30, make-up air is able tobe drawn into the fuel tank 35 and alternately, excess pressure in thefuel tank 35 is able to be relieved without releasing any substantialamount of fuel vapor to the outside atmosphere. This is particularlybeneficial to prevent exposure of an operator to any substantial amountof fuel vapor during operation (e.g., operating a lawn mower, riding anoff-road vehicle, etc.).

In some embodiments and under some circumstances, fuel vapor may bereleased to the outside atmosphere when the cap 25 is removed from theopening 30. In some embodiments and under some circumstances, fuel vaporcomponents are trapped in the membrane 90 during one condition (e.g.,warm fuel sitting in the fuel tank 35 with the associated internalcombustion engine idling or off) and substantially cleared from themembrane during another condition (e.g., running of the internalcombustion engine with make-up air entering the fuel tank 35 through thecap 25).

Regardless of the membrane material, the cap 25 and fuel storage system20 may be incorporated with an evaporative emissions system includingadditional emissions-treating components and/or flow-controllingcomponents. In some embodiments, a carbon canister is included to filterfuel vapor and retain selected chemical compounds of the fuel vaportherein. The selected chemical compounds are then partially or whollyburned with the fuel in the internal combustion engine of the vehicle,apparatus, etc. As discussed in detail in U.S. patent application Ser.No. 11/058,063, filed Feb. 14, 2005, now published as U.S. PatentApplication Publication No. 2006/0011173, entire contents of which ishereby incorporated by reference.

In some aspects and in some constructions, the membrane 90 can be of amaterial and configuration/structure to present leakage of liquid fuelfrom within the fuel tank 35 while allowing flow of gaseous substancestherethrough. In some aspects and in some constructions. the membrane 90can be of a material and configuration/structure to prevent leakage ofliquid fuel and select gaseous substances such as fuel vapor whileallowing flow of other gaseous substances such as air therethrough.

In some constructions, the membrane 90 resists the build-up of varnishesfrom fuels. Additionally, dirt and debris (whether from inside the fueltank 35 or the outside atmosphere) are prevented from reducing thegaseous flow capacity of the membrane 90. In some constructions, a feltdust seal is provided integral with or adjacent to the vent. Themembrane 90 prevents liquid fuels from escaping a tank during virtuallyall modes of operation, including: normal running, roll over condition,storage, service/maintenance, etc.

The membrane 90 may provide an oleophobic and/or hydrophobic filter, asdiscussed above. The membrane 90 may be similar to that described andillustrated in U.S. Pat. No. 6,579,342 issued Jan. 17, 2003, the entirecontents of which is hereby incorporated by reference.

FIG. 5 illustrates a cap 105 similar to that illustrated in FIGS. 1-4 inall aspects except for the cover 110, which is districtive to thisembodiment. As such, all reference numerals except those relating to thecover 110 are carried over from the first embodiment. The cover 110includes a nipple 115 projecting outwardly from an external surface anddefining a vent aperture 117. Although the nipple 115 is shown as havinga barb thereon, it may alternatively be threaded or attachable to matingstructure with hose clamps, compression fittings, etc. The nipple 115provides a connection structure for extending the flow path from thefuel tank 35 and chamber 75 to a remote location. As in the firstembodiment, the flow path provides communication between the inside ofthe fuel tank 35 and the outside atmosphere.

As shown in FIG. 6, a fuel storage system 120 includes the cap 105coupled to the opening 30 of the fuel tank 35. A hose 125 is coupled tothe nipple 115 of the cap 105. The hose 125 has a remote end 127 fixedat location remote from the cap 105 and in either direct or indirectcommunication with the outside atmosphere. In some constructions, thehose 125 couples the cap 105 to a carbon canister, especially in anapplication in which the associated apparatus having an internalcombustion engine is regulated for evaporative emissions levels. Thus,the fuel storage system 120 is a part of an evaporative emissions systemin such constructions. The evaporative emissions system may includecertain functional aspects and components as discussed in U.S. PatentApplication Publication No. 2006/0011173. Such additional aspects and/orcomponents are equally applicable to the alternate constructionsdiscussed below.

In other embodiments, a carbon canister is not coupled to the hose 125.In such embodiments, it may not be necessary to restrict the release offuel vapor alternately, other means may be provided for restricting therelease of fuel vapor from the fuel tank 35, such as a membrane materialconstructed to inhibit the passage of fuel vapor. As such, the hose 125may be unsubstantially open-ended at its remote end 127. The remotelocation may be a more desirable location than the location of the cap105 to vent to and/or draw from.

FIGS. 7-9 illustrate a remote vent structure 220 for installation in aclosed system, such as a fuel storage system 230, incorporating themembrane 90. The vent structure 220 can be placed in the fuel storagesystem 230 remotely from a cap 232, which mates to an opening of a fueltank 233. The cap 232 need not be vented as the remote vent structure220 provides venting for the fuel storage system 230.

In the illustrated construction, the vent structure 220 includes ahousing 234, a ramp 238, and a cover 242. The cover 242 includes a port246, which may be connected to a tube, hose, or other conduit. Themembrane 90 is disposed between the housing 234 and the cover 242. Thehousing 234 defines a path from the fuel tank 233 to the port 246 in thecover 242. The membrane 90 is positioned in the flow path between theinterior of the housing 234 and the port 246 in the cover 242.Accordingly, for any adaptable gas and/or liquid to pass between theinferior of the fuel storage system 230 and the exterior of the fuelstorage system 230, such gas and/or liquid must pass through themembrane 90.

Mounting of the membrane 90 within the vent structure 220 may includemethods similar to those discussed above with respect to the cap 25.However, the vent structure 220 provides a different accommodatingstructure for the membrane 90. A flat upper wall of the housing 234provides a resting surface for the membrane 90. The cover 242 includes apocket 248, which is substantially form-fitting around the peripheralrim portion 92 of the membrane 90. The membrane 90 may be substantiallyself-sealing around the peripheral rim portion 92, or alternately,fastening and sealing means may be provided as discussed above withrespect to the cap 25.

In yet another construction shown in FIG. 10, a vent structure 250 witha separator membrane 254 is configured to be mounted within a fuel tank258 of a fuel storage system 262. The separator membrane 254 may belocated adjacent a vent head 266 (e.g., an integrally formed pocket inan upper wall 270 of the fuel tank 258). A tube 274 is coupled to themembrane 254 and open to the volume defined by the vent head 266. Thetube 274 is routed through the bottom wall 278 of the fuel tank 258 witha fitting 282 to fluidly couple the volume within the vent head 266 tothe outside of the fuel tank 258. A cap 232, which is simple and notnecessarily vented, is provided as in the embodiment of FIG. 9.

The vent structure 250 allows venting the fueled tank 258 to and fromthe vent head 266. The volume of the vent head 266 is blocked from theliquid fuel within the fuel tank 258 by the membrane 254, which mat beidentical to the membrane 90 described above except for the particularshape required to couple the membrane 254 with the vent head 266 and thetube 274. As shown in FIG. 10, the membrane 254 includes a centralaperture 286, which sealingly mates to the tube 274. An outer peripheryof the membrane 254 sealingly mates to the fuel tank 258 at the venthead 266.

In yet another construction shown in FIG. 11, a vent structure 300 witha separator membrane 304 is configured to be mounted within a fuel tank308 of a fuel storage system 312. The membrane 304 is formed to definean interior volume, which is in fluid communication with the inside of atube 316. The membrane 304 is formed with a central aperture 320, whichsealingly mates with the tube 316. The membrane 304 is positionedgenerally at the top of the fuel tank 308, and the tube 316 couples theinterior volume of the membrane 304 with the atmosphere outside the fueltank 308 by existing through a bottom wall 324 of the fuel tank 308.Other than its specific form, the membrane 304 is similar to themembranes 90 and 254 described above, including alternate materials,performance, etc. thereof as discussed throughout.

The following tables and graphs illustrate the venting requirements of asystem, such as the fuel system included for a small engine. In thetables and graphs, the vent with the membrane allows sufficient flow ofmake up air into the tank/system so that the engine operates properly.“Vent” is used generally to encompass vents in caps and remote vents,and membrane encompasses any of the membranes illustrated in the figuresand/or described herein. The vent has sufficient air vapor flow throughit to provide the venting of air and vapors generated, for example, formthe diurnal temperature cycles and/or the excessive temperature changestypically seen in small off highway engine equipment. The membraneallows venting of internal tank pressure without undo pressure build-upin the tank.

TABLE 1 Crystal with 0.060″ orifice Crystal with 0.125″ orifice PressureSpecimen Specimen Specimen Specimen Specimen Specimen (psi) # 1 # 2 # 3# 4 # 5 # 6 Air flow 0.25 5500 5200 4700 10000 10300 9400 (ccm) 0.507900 7800 7100 15100 16000 14700 0.75 10000 10000 9200 19100 19600 187001.00 11400 11800 10900 22000 23100 22100 1.25 12800 13200 12100 2470025400 24500 1.50 14200 14600 13400 26900 27400 26400 1.75 15400 1590014800 28100 28700 28000 2.00 16400 17000 15600 29000 29300 28800

TABLE 2 Crystal with covered vent Pressure Specimen Specimen (psi) # 7 #8 Air flow 0.25 6000 7000 (ccm) 0.50 9200 11500 0.75 11400 14600 1.0013100 17400 1.25 15100 19400 1.50 16900 21600 1.75 18400 23600 2.0019900 25000

TABLE 3 Engine hp gal/hr cc/hr range cc/m range 1 1.1 4138 4637 69 77 21.2 4514 5059 75 84 3 1.3 4890 5480 82 91 4 1.4 5266 5902 88 98 5 1.55643 6324 94 105 6 1.6 6019 6745 100 112 7 1.7 6395 7167 107 119 8 1.86771 7588 113 126 9 1.9 7147 8010 119 133 10 2 7523 8431 125 141 12 2.28276 9275 138 155 15 2.5 9404 10539 157 176 18 2.8 10533 11804 176 19720 3 11285 12647 188 211 25 3.5 13166 14755 219 246 30 4 15047 16863 251281

1. A fuel evaporative emissions system for a vehicle or motor-drivenpower equipment comprising a storage tank for holding a volume of fuel;a vent structure at least partially defining a passageway between theinside of the storage tank and the outside atmosphere; and a separatormembrane positioned within the vent structure configured to block liquidfuel in the storage tank from reaching the outside atmosphere throughthe passageway, the separator membrane being permeable by air; whereinthe vent structure includes at least one of a cap, and a storage tank.2. The fuel evaporative emissions system of claim 1, wherein the ventstructure includes a cap configured to close an opening of the storagetank, the cap having a main body with a vent aperture formed therein. 3.The fuel evaporative emissions system of claim 2, wherein the capincludes a cover coupled to the main body and at least partiallydefining a chamber in communication with the vent aperture in which theseparator membrane is mounted.
 4. The fuel evaporative emissions systemof claim 3, wherein the main body is formed with an annular willextending into the chamber, the separator membrane being boned to theannular wall.
 5. The fuel evaporative emissions system of claim 4,wherein the separator membrane includes a peripheral rim that is weldedto the annular wall.
 6. The fuel evaporative emissions system of claim1, further comprising a carbon canister between the vent structure andthe outside atmosphere along the passageway for removing selectedcomponents of fuel vapor existing the storage tank.
 7. The fuelevaporative emissions system of claim 1, wherein the separator membranesubstantially blocks fuel vapors from reaching the outside atmospherethrough the passageway.
 8. The fuel evaporative emissions system ofclaim 7, wherein the separator membrane is in direct contact with theoutside atmosphere.
 9. A vent structure for a fuel system comprising: ahousing at least partially defining a chamber; and a separator membranepositioned within the chamber, the separator membrane being impermeableto liquid and permeable to select gases; wherein the separator membraneincludes a peripheral rim, said rim being bonded to the housing.
 10. Thevent structure of claim 9, wherein the housing is part of a fuel capconfigured to close an opening of a fuel containment structure of thefuel system.
 11. The vent structure of claim 10, wherein the fuel capincludes a first end configured to mate with the opening and a secondend opposite the first end, a cover member being attached to the fuelcap at the second end, wherein the cover member is formed with anopening in communication with the chamber and the separator membrane.12. The vent structure of claim 11, further comprising a hose coupled tothe opening in the cover member and having a remote end positioned at aremote location from the fuel cap.
 13. The vent structure of claim 12,further comprising an air filer positioned adjacent the remote location.14. The vent structure of claim 12, further comprising a carbon canistercoupled to the remote end of the hose.
 15. The vent structure of claim9, wherein the rim of the separator membrane is welded to the housing.16. The vent structure of claim 9, wherein the housing is part of aremote vent that is coupled to a fuel containment structure of the fuelsystem.
 17. A fuel cap configured for attachment to a fuel containmentstructure of a vehicle or other motor-driven power equipment comprising:a main body portion having a vent aperture formed therein; a chamber atleast partially defined by the main body portion; an external opening incommunication with the chamber and with a surrounding atmosphere; and aseparator membrane positioned within the chamber, the separator membranebeing primarily constructed of a material that blocks liquid fuel withinthe fuel containment structure from reaching the external opening andthat allows air to flow into and out of the fuel containment structureas necessary to avoid substantial deviation from atmosphere pressurewithin the fuel containment structure.
 18. The fuel cap of claim 17,wherein the separator membrane is primarily constructed of a materialthat substantially blocks the passage of hydrocarbon fuel vapor from thefuel containment structure to the surrounding atmosphere.
 19. The fuelcap of claim 18, wherein the fuel cap is configured to substantiallyeliminate the emission of hydrocarbon fuel vapor from within the fuelcontainment structure without the use of a carbon canister.
 20. The fuelof claim 17, wherein the external opening is in communication with thesurrounding atmosphere with a carbon canister therebetween.